The detectors are being added as part of a pilot program instituted by Major League Baseball. The league said it is working with the U.S. Department of Homeland Security to standardize security procedures at all 30 MLB ballparks by the start of the 2015 season.

"We fully support MLB's efforts to implement these enhanced security measures, and look forward to working with them during this pilot program," Sal DeAngelis, the Phillies Director of Operations/Security, said in a statement.

Fans entering Citizens Bank Park through the Right Field Gate will be required to pass through the detectors starting at the July 21st game against the San Francisco Giants, the team said. They will undergo the screening before having their tickets scanned.

Team officials say cell phones, cameras and other large metal items will need to be put aside as fans enter the detectors. But, fans will not be required to remove belts or shoes. Bag checks will also remain.

DeAngelis said he expects the team to install the metal detectors at every gate by the start of next season.